“The specialist serves as a striking concrete example of the species, making clear to us the radical nature of the novelty. For, previously, men could be divided simply into the learned and the ignorant, those more or less the one, and those more or less the other. But your specialist cannot be brought in under either of these two categories. He is not learned, for he is formally ignorant of all that does not enter into his speciality; but neither is he ignorant, because he is "a scientist," and "knows" very well his own tiny portion of the universe. We shall have to say that he is a learned ignoramus, which is a very serious matter, as it implies that he is a person who is ignorant, not in the fashion of the ignorant man, but with an the petulance of one who is learned in his own special line.”

1960s, Operating Manual for Spaceship Earth (1963)
Context: Every time man makes a new experiment he always learns more. He cannot learn less. He may learn that what he thought was true was not true. By the elimination of a false premise, his basic capital wealth which in his given lifetime is disembarrassed of further preoccupation with considerations of how to employ a worthless time-consuming hypothesis. Freeing his time for its more effective exploratory investment is to give man increased wealth.

Eminent Indians (1947)

Speech before a gathering of physicians (circa 1922) http://books.google.com/books?id=qYIHAAAAMAAJ&q=%22a+specialist+is+a+man+who+knows+more+and+more+about+less+and+less%22&pg=PA35#v=onepage

Original: L'ignorante pecca spesso di educazione, arroganza e presunzione. Per lui è normale comportarsi così perché non è abituato ad acquisire cultura, secondo lui nasce saggio e generalmente per la sua natura chiusa muore sempre insieme alla sua ignoranza.
Source: prevale.net

1963, Address at Vanderbilt University

Arrowsmith (1925)
Context: Perhaps I am a crank, Martin. There are many who hate me. There are plots against me—oh, you t'ink I imagine it, but you shall see! I make many mistakes. But one thing I keep always pure: the religion of a scientist.
To be a scientist—it is not just a different job, so that a man should choose between being a scientist and being an explorer or a bond-salesman or a physician or a king or a farmer. It is a tangle of ver-y obscure emotions, like mysticism, or wanting to write poetry; it makes its victim all different from the good normal man. The normal man, he does not care much what he does except that he should eat and sleep and make love. But the scientist is intensely religious—he is so religious that he will not accept quarter-truths, because they are an insult to his faith.
He wants that everything should be subject to inexorable laws. He is equal opposed to the capitalists who t'ink their silly money-grabbing is a system, and to liberals who t'ink man is not a fighting animal; he takes both the American booster and the European aristocrat, and he ignores all their blithering. Ignores it! All of it! He hates the preachers who talk their fables, but he iss not too kindly to the anthropologists and historians who can only make guesses, yet they have the nerf to call themselves scientists! Oh, yes, he is a man that all nice good-natured people should naturally hate! ~ Gottlieb, Ch. 26

Source: Education of a Wandering Man (1989), Ch. 11